ABSTRACT The Flow Cytometry & Cell Sorting Shared Resource (FCSR) was established in 1988 to provide flow cytometry support to researchers of the Georgetown Lombardi Comprehensive Cancer Center (LCCC). The Cancer Center Support Grant (CCSG) has supported the FCSR since 1990. Karen Creswell, PhD, who has been with the FCSR since 1991, is director. The purpose of the FCSR is to apply a wide range of flow cytometric and fluorescence-activated cell sorting solutions to problems in cancer research. The FCSR provides comprehensive support to facilitate utilization of this technology by a variety of investigators. Specifically, the FCSR 1) maintains three flow cytometers/cell sorters, which are the only instruments with cell sorting capability at Georgetown University (Georgetown); 2) provides trained operators to ensure efficient and correct use of this complex instrumentation and to assist with data interpretation; 3) provides personnel to assist with applying a variety of fluorescence-labeling methods; and 4) provides expertise for the innovative application of this instrumentation to fully exploit its capabilities for cancer research. Since the last site visit, the FCSR has seen an increase in use and an expansion of projects with more complex phenotyping experiments. In fiscal year (FY) 2017, 20 peer review-funded researchers from three LCCC programs used FCSR services as important tools in their research. The FCSR provides value to research projects by separating cells based on transfection markers, such as enhanced green fluorescent protein, stem cell markers and other cell surface markers. Functional assays of the cell cycle, apoptotic status and oxidative stress are performed in addition to phenotyping. Immunophenotyping of mouse and human tissues and tumor- infiltrating lymphocytes (TILs) has increased due to the 14-color capabilities of the Fortessa. Through the Mid- Atlantic Shared Resource Consortium (MASRC), LCCC investigators have access to state-of-the-art CyTOF analyses and informatics solutions. These assays allow researchers to quickly and effectively assess the phenotype and function of cell populations in their research. Future plans for the FCSR include expanded support of immunotherapy research in collaboration with investigators at the John Theurer Cancer Center (JTCC) on the New Jersey campus of the LCCC Consortium (LCCC-NJ).